Reservoir completion systems installed in production, injection, and storage wells often incorporate sand screens positioned across the reservoir sections to prevent sand and other solids particles over a certain size from entering the reservoir completion. Conventional sand screen joints are typically assembled by wrapping a filter media around a perforated basepipe so fluids entering the sand screen from the wellbore must first pass through the filter media. Solid particles over a certain size will not pass through the filter media and will be prevented from entering the reservoir completion.
For example, a reservoir completion system 10 in FIG. 1 has completion screen joints 50 deployed on a completion string 14 in a borehole 12. Typically, these screen joints 50 are used for vertical, horizontal, or deviated boreholes passing in an unconsolidated formation, and packers 16 or other isolation elements can be used between the various joints 50. During production, fluid produced from the borehole 12 directs through the screen joints 50 and up the completion string 14 to the surface rig 18. The screen joints 50 keep out fines and other particulates in the produced fluid. In this way, the screen joints 50 can prevent the production of reservoir solids and in turn mitigate erosion damage to both well and surface components and can prevent other problems associated with fines and particulate present in the produced fluid.
In long horizontal wellbores, there can be a tendency for fluids to preferentially enter the reservoir completion at specific points along its length either by virtue of the properties of the reservoir rock or through the effects of flowing friction. This effect can be undesirable as it will cause uneven reservoir drainage or injection. In these circumstances, it can be beneficial to incorporate inflow control devices (ICDs) into the reservoir completion. Typically, one inflow control device is attached to each sand screen joint 50.
Sand screen joints 50 incorporating inflow control devices are manufactured so that the filter media is wrapped around a drainage layer or support rods (depending on the filter media type), which are positioned on un-perforated portions of the basepipe. The only perforations in the basepipe are positioned beneath the inflow control device.
During production, reservoir fluids travel through the filter media of the sand screen joint 50 and then along the annular gap between the filter media and the basepipe of the screen. Next, the produced fluid passes through a flow restriction (e.g., a tungsten carbide nozzle) and into a housing of the inflow control device before passing through the perforations in the basepipe and into the reservoir completion.
Examples of inflow control devices are disclosed in U.S. Pat. No. 5,435,393 to Brekke et al.; U.S. Pat. No. 7,419,002 to Dybevik et al.; U.S. Pat. No. 7,559,375 to Dybevik et al.; and U.S. Pat. No. 8,096,351 to Peterson et al. Other examples of inflow control devices are also available, including the FloReg ICD available from Weatherford International, the Equalizer® ICD available from Baker Hughes, ResFlow ICD available from Schlumberger, and the EquiFlow® ICD available from Halliburton. (EQUALIZER is a registered trademark of Baker Hughes Incorporated, and EQUIFLOW is a registered trademark of Halliburton Energy Services, Inc.)
Turning to FIGS. 2A-2C, a prior art completion screen joint 50 having an inflow control device 70 is shown in a side view, a partial side cross-sectional view, and a detailed view. The screen joint 50 has a basepipe 52 with a sand control jacket 60 and inflow control device 70 disposed thereon. The basepipe 52 defines a through-bore 55 and has a coupling crossover 56 at one end for connecting to another joint or the like. The other end 54 can connect to a crossover (not shown) of another joint on the completion string. Inside the through-bore 55, the basepipe 52 defines pipe ports 58 where the inflow control device 70 is disposed.
The joint 50 is connected to a production string (14: FIG. 1) with the screen 60 typically mounted upstream of the inflow control device 70. Here, the inflow control device 70 is similar to the FloReg Inflow Control Device (ICD) available from Weatherford International. As best shown in FIG. 2C, the device 70 has an outer sleeve 72 disposed about the basepipe 52 at the location of the pipe ports 58. A first end-ring 74 seals to the basepipe 52 with a seal element 75, and a second end-ring 76 attaches to the end of the screen 60. Overall, the sleeve 72 defines an annular space around the basepipe 52 that communicates the pipe ports 58 with the sand control jacket 60. The second end-ring 76 has flow ports 80, which separate the sleeve's inner space 86 from the screen 60.
For its part, the sand control jacket 60 is disposed around the outside of the basepipe 52. As shown, the sand control jacket 60 can be a wire wrapped screen having rods or ribs 64 arranged longitudinally along the basepipe 52 with windings of wire 62 wrapped thereabout to form various slots. Fluid from the surrounding borehole annulus can pass through the annular gaps and travel between the sand control jacket 60 and the basepipe 52.
Internally, the inflow control device 70 has nozzles 82 disposed in flow ports 80. The nozzles 82 restrict the flow of screened fluid from the screen jacket 60 into the device's inner space 86 and produce a pressure drop in the fluid. For example, the inflow control device 70 can have ten nozzles 82. Operators set a number of these nozzles 82 open at the surface to configure the device 70 for use downhole in a given implementation. In this way, the device 70 can produce a configurable pressure drop along the screen jacket 60 depending on the number of open nozzles 82.
To configure the device 70, pins 84 can be selectively placed in the passages of the nozzles 82 to close them off. The pins 84 are typically hammered in place with a tight interference fit and are removed by gripping the pin 84 with a vice grip and then hammering on the vice grip to force the pin 84 out of the nozzle 82. These operations need to be performed off rig beforehand so that valuable rig time is not used up. Thus, operators must predetermine how the inflow control devices 70 are to be preconfigured and deployed downhole before setting up the components for the rig.
As fluid flows through the flow nozzles 82 in each inflow control device 70, a pressure drop is created. By plugging a pre-determined quantity of the nozzles 82 in each inflow control device 70 on each sand screen 60, operators can adjust the pressure drop produced along the length of the completion and can consequently configured the production/injection profile of the completion.
When the joints 50 are used in a horizontal or deviated borehole of a well as shown in FIG. 1, the inflow control devices 70 are configured to produce particular pressure drops to help evenly distribute the flow along the completion string 14 and prevent coning of water in the heel section. Overall, the devices 70 choke production to create an even-flowing pressure-drop profile along the length of the horizontal or deviated section of the borehole 12.
Typically, the reservoir section of a well is under positive pressure that acts to force reservoir fluids into the reservoir completion. During completion, work over, intervention and other operational periods when the well is not being produced, the reservoir pressure must be controlled to prevent reservoir fluids from migrating to surface. This is typically achieved by filling the well with a weighted fluid that will counteract the reservoir pressure.
For example, well kill operations may need to be performed through the completion system 10. In these situations, the weighted fluid transmits pressure to the formation down the reservoir completion. Pressure is transmitted down the tubulars to the basepipe 52, through the perforations 58 in the basepipe 52, and into the inflow control device 70. From here, the pressure then passes through the open flow nozzles 82, along the non-perforated portion of the basepipe 52, and finally out through the screen section 60. FIG. 2C shows the path of such pressure transmission.
A situation can arise where the balance between the fluid weight and the reservoir pressure is lost, and fluid either begins to flow into or out of the reservoir in an uncontrolled manner. In these situations, it is necessary to re-gain control of the fluid balance through a process called “killing the well”.
Killing the well is typically achieved by circulating a weighted fluid into the well that places a significantly high enough pressure against the wellbore to overcome the reservoir pressure. It is also necessary to prevent this weighted fluid from continuing to leak into the reservoir section. This is achieved by mixing a Loss Control Material (LCM) in with the weighted fluid. LCM can be made up of solid particles of a specific size that are designed to rest against the area where the fluid is leaking into the reservoir section. The solid particles bridge off at the area to plug off the leak temporarily.
When conventional sand screens without inflow control devices are used in the completion across a reservoir section, the LCM will bridge off against the inside diameter of the filter media of the sand screen. Once the balance between the fluid in the wellbore and the reservoir pressure has been re-established, the fluid from the well can be produced to the surface in a controlled manner that will lift the LCM away from the filter media of the sand screen and re-establish the flow path.
In wells where sand screen joints 50 incorporating inflow control devices 70 are installed across the wellbore, successfully killing the well can prove more difficult. Due to the inflow control devices 70, the LCM does not have a clear path to the inside of the filter media in each sand screen joint 50 during the process of killing the well. Also, it may also be difficult to successfully remove the LCM from the inside diameter of the filter media due to the restricted flow path through the inflow control device 70. This difficulty in removing the LCM can have an impact on the ability to successfully produce or inject from the well after the event.
One technique for addressing this issue involves installing a section of sized filter media on a valve at the inlet to the inflow control device 70. This allows the LCM to bridge off across this filter media and kill the well against the valve. In this scenario, the LCM does not need to flow into the sand screen joint 50 and does not need to bridge against the inside of the filter media. This method is disclosed in U.S. Pat. No. 7,644,758 to Coronado et al.
Although the inflow control devices of the prior art may be effective, it is desirable to be able to configure the pressure drop for a borehole and to kill the well using LCM in more reliable ways.
The subject matter of the present disclosure is, therefore, directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.